This invention is related to the field of organometal catalyst compositions.
The production of polymers is a multi-billion dollar business. This business produces billions of pounds of polymers each year. Millions of dollars have been spent on developing technologies that can add value to this business.
One of these technologies is called metallocene catalyst technology. Metallocene catalysts have been known since about 1958. However, their low productivity did not allow them to be commercialized. About 1974, it was discovered that contacting one part water with one part trimethylaluminum to form methyl aluminoxane, and then contacting such methyl aluminoxane with a metallocene compound, formed a metallocene catalyst that had greater activity. However, it was soon realized that large amounts of expensive methyl aluminoxane were needed to form an active metallocene catalyst. This has been a significant impediment to the commercialization of metallocene catalysts.
Fluoro-organo borate compounds have been used in place of large amounts of methyl aluminoxane. However, this is not satisfactory, since such borate compounds are very sensitive to poisons and decomposition, and can also be very expensive.
It should also be noted that having a heterogeneous catalyst is important. This is because heterogeneous catalysts are required for most modern commercial polymerization processes. Furthermore, heterogeneous catalysts can lead to the formation of substantially uniform polymer particles that have a high bulk density. These types of substantially uniform particles are desirable because they improve the efficiency of polymer production and transportation. Efforts have been made to produce heterogeneous metallocene catalysts; however, these catalysts have not been entirely satisfactory.
Bridged fluorenyl zirconium metallocenes hold a special place in the development of loop-slurry polyethylene technology. Such compounds are known for their excellent ability to incorporate hexene efficiently, which is important in a loop-slurry process. They also are capable of producing very high molecular weight polymer,which is difficult for bis-cyclopentadienyl zirconium species, or even for bis-indenyl zirconium species. Some, notably [2-(xcex75-cyclopentadienyl)-2-(xcex75-fluoren-9-yl)hex-5-ene]zirconium(IV) dichloride, produce exceptionally transparent and glossy films and other manufactures. Bridged fluorenyl zirconium metallocenes are activated well enough by methyl aluminoxanes (MAO), but unfortunately MAO is expensive and in the liquid state tends to cause fouling in the reactor.
An object of this invention is to provide a process that produces a catalyst composition that can be used to polymerize at least one monomer to produce a polymer.
Another object of this invention is to provide the catalyst composition.
Another object of this invention is to provide a process comprising contacting at least one monomer and the catalyst composition under polymerization conditions to produce the polymer.
Another object of this invention is to provide an article that comprises the polymer produced with the catalyst composition of this invention.
In accordance with one embodiment of this invention, a process to produce a catalyst composition is provided. The process comprises (or optionally, xe2x80x9cconsists essentially of,xe2x80x9d or xe2x80x9cconsists ofxe2x80x9d):
1) contacting at least one organometal compound and at least one first organoaluminum compound to produce an organometal/organoalurinumn mixture;
wherein the organometal compound has the following general formula:
(X1)(X2)(X3)(X4)M1
wherein M1 is selected from the group consisting of titanium, zirconium, and hafnium;
wherein (X1) and (X2) are cyclopentadienyl derivatives and at least one is a fluorenyl or substituted fluorenyl;
wherein cyclopentadienyl derivatives are selected from the group consisting of cyclopentadienyls, indenyls, fluorenyls, substituted cyclopentadienyls, substituted indenyls, and substituted fluorenyls;
wherein substituents on the substituted cyclopentadienyls, substituted indenyls, and substituted fluorenyls of(X1) and (X2) are selected from the group consisting of aliphatic groups, cyclic groups, combinations of aliphatic and cyclic groups, silyl groups, alkyl halide groups, halides, organometallic groups, phosphorus groups, nitrogen groups, oxygen groups, silicon, phosphorus, boron, germanium, and hydrogen;
wherein (X1) and (X2) are connected by a bridge having one or two atoms between (X1) and (X2); and further wherein the one or two atoms of the bridge can contain substituents;
wherein (X3) and (X4) are independently selected from the group consisting of halides, aliphatic groups, substituted aliphatic groups, cyclic groups, substituted cyclic groups, combinations of aliphatic groups and cyclic groups, combinations of substituted aliphatic groups and cyclic groups, combinations of aliphatic groups and substituted cyclic groups, combinations of substituted aliphatic groups and substituted cyclic groups, amido groups, substituted amido groups, phosphido groups, substituted phosphido groups, alkyloxide groups, substituted alkyloxide groups, aryloxide groups, substituted aryloxide groups, organometallic groups, and substituted organometallic groups; and
wherein the first organoaluminum compound is selected from the group consisting of triethyl aluminum, tripropyl aluminum, and tri-n-butyl aluminum;
2) contacting the organometal/organoaluminum mixture with a treated solid oxide compound and optionally, at least one second organoaluminum compound;
wherein the second organoaluminum compound is added in a reactor, and is represented by the following formula:
xe2x80x83Al(X5)n(X6)3xe2x88x92n
wherein (X5) is a hydrocarbyl having from 1 to about 20 carbon atoms;
wherein (X6) is a halide, hydride, or alkoxide; and
wherein xe2x80x9cnxe2x80x9d is a number from 1 to 3 inclusive; and;
wherein the treated solid oxide compound is produced by a process comprising: a) contacting at least one solid oxide compound with at least one electron-withdrawing anion source compound; b) optionally, also contacting the solid oxide compound with at least one metal salt compound; and c) calcining the solid oxide compound before, during, or after contacting the electron-withdrawing anion source compound or metal salt compound to produce the treated solid oxide compound.
In accordance with a second embodiment of this invention, a process is provided comprising contacting at least one monomer and the catalyst composition under polymerization conditions to produce a polymer.
In accordance with a third embodiment of this invention, an article is provided. The article comprises the polymer produced in accordance with this invention.
These objects, and other objects, will become more apparent to those with ordinary skill in the art after reading this disclosure.
A process to produce a catalyst composition is provided. The process comprises contacting at least one organometal compound and at least one first organoaluminum compound to produce an organometal/organoaluminum mixture. Then, contacting the organometal/organoaluminum mixture with a treated solid oxide compound and optionally, at least one second organoaluminum compound to produce the catalyst composition.
The organometal compound utilized in this invention has the following general formula:
(X1)(X2)(X3)(X4)M1
M1 is selected from the group consisting of titanium, zirconium, and hafnium. Preferably, M1 is zirconium.
(X1) and (X2) are cyclopentadienyl derivatives and at least one is a fluorenyl or substituted fluorenyl. Cyclopentadienyl derivatives are selected from the group consisting of cyclopentadienyls, indenyls, fluorenyls, substituted cyclopentadienyls, substituted indenyls, and substituted fluorenyls. Preferably, (X1) or (X2) is cyclopentadienyl.
Substituents on the substituted cyclopentadienyls, substituted indenyls, and substituted fluorenyls of (X1) and (X2) are selected from the group consisting of aliphatic groups, cyclic groups, combinations of aliphatic and cyclic groups, silyl groups, alkyl halide groups, halides, organometallic groups, phosphorus groups, nitrogen groups, oxygen groups, silicon, phosphorus, boron, germanium, and hydrogen.
Suitable examples of aliphatic groups are hydrocarbyls, such as, for example, paraffins and olefins. Suitable examples of cyclic groups are cycloparaffins, cycloolefins, cycloacetylenes, and arenes. Substituted silyl groups include, but are not limited to, alkylsilyl groups where each alkyl group contains from 1 to about 12 carbon atoms, arylsilyl groups, and arylalkylsilyl groups. Suitable alkyl halide groups have alkyl groups with 1 to about 12 carbon atoms. Suitable organometallic groups include, but are not limited to, substituted silyl derivatives, substituted tin groups, substituted germanium groups, and substituted boron groups.
Suitable examples of such substituents are methyl, ethyl, propyl, butyl, tert-butyl, isobutyl, amyl, isoamyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, dodecyl, 2-ethylhexyl, pentenyl, butenyl, phenyl, chloro, bromo, iodo, trimethylsilyl, and phenyloctylsilyl.
(X1) or (X2) are connected by a bridge having one or two atoms between (X1) and (X2). The one or two atoms in the bridge can contain substituents. Preferably, the bridge has one atom connecting (X1) and (X2). The atoms of the bridge can be carbon or silicon, optionally substituted with alkyl or aryl radicals. A substituted single carbon bridge is preferred.
(X3) and (X4) are independently selected from the group consisting of halides, aliphatic groups, substituted aliphatic groups, cyclic groups, substituted cyclic groups, combinations of aliphatic groups and cyclic groups, combinations of substituted aliphatic groups and cyclic groups, combinations of aliphatic groups and substituted cyclic groups, combinations of substituted aliphatic groups and substituted cyclic groups, arido groups, substituted amido groups, phosphido groups, substituted phosphido groups, alkyloxide groups, substituted alkyloxide groups, aryloxide groups, substituted aryloxide groups, organometallic groups, and substituted organometallic groups; aryloxide groups, organometallic groups, and substituted organometallic groups.
Suitable examples of aliphatic groups are hydrocarbyls, such as, for example, paraffins and olefins. Suitable examples of cyclic groups are cycloparaffins, cycloolefins, cycloacetylenes, and arenes. Currently, it is preferred when (X3) and (X4) are selected from the group consisting of halides and hydrocarbyls, where such hydrocarbyls have from 1 to about 10 carbon atoms. However, it is most preferred when (X3) and (X4) are selected from the group consisting of fluoro, chloro, and methyl.
Suitable examples of aliphatic groups are hydrocarbyls, such as, for example, paraffins and olefins. Suitable examples of cyclic groups are cycloparaffins, cycloolefins, cycloacetylenes, and arenes. Suitable organometallic groups include, but are not limited to, substituted silyl derivatives, substituted tin groups, substituted germanium groups, and substituted boron groups.
Various processes are known to make these organometal compounds. See, for example, U.S. Pat. Nos. 4,939,217; 5,210,352; 5,436,305; 5,401,817; 5,631,335, 5,571,880; 5,191,132; 5,480,848; 5,399,636; 5,565,592; 5,347,026; 5,594,078; 5,498,581; 5,496,781; 5,563,284; 5,554,795; 5,420,320; 5,451,649; 5,541,272; 5,705,478; 5,631,203; 5,654,454; 5,705,579; and 5,668,230; the entire disclosures of which are hereby incorporated by reference.
Bridged fluorenyl zirconium structures of utility in this invention as organometal compounds include 1,2-ethanediylbis(9-fluorenyl)zirconium dichloride; (organometal A), diphenylmethanediyl(9-fluorenyl, cyclopentadienyl)zirconium dichloride (organometal B), and phenylmethylmethanediyl(9-fluorenyl, cyclopentadienyl)zirconium dichloride (organometal C), [2-(xcex75-cyclopentadienyl)-2-(xcex75-fluoren-9-yl)hex-5-ene]zirconium(IV) dichloride (organometal D). These structures are shown below. 
Preferably, the organometal compound is organometal D.
The first organoaluminum compound is selected from the group consisting of triethyl aluminum (TEA), tripropyl aluminum, and tri-n-butyl aluminum. Preferably, the first organoaluminum compound is TEA.
Optionally, at least one second organoaluminum compound also can be added to a reactor directly as a cocatalyst. The second organoaluminum compound has the following general formula:
Al(X5)n(X6)3xe2x88x92n
In this formula, (X5) is a hydrocarbyl having from 1 to about 20 carbon atoms. Currently, it is preferred when (X5) is a linear alkyl having from 1 to about 10 carbon atoms. However, it is most preferred when (X5) is selected from the group consisting of ethyl, propyl, and butyl.
In this formula, (X6) is a halide, hydride, or alkoxide. Currently, it is preferred when (X6) is independently selected from the group consisting of fluoro and chloro. However, it is most preferred when (X6) is chloro.
In this formula, xe2x80x9cnxe2x80x9d is a number from 1 to 3 inclusive. However, it is preferred when xe2x80x9cnxe2x80x9d is 3.
Examples of such compounds are as follows:
trimethyl aluminum;
triethyl aluminum (TEA);
tripropyl aluminum;
diethylaluminum ethoxide;
tributylaluminum;
diisobutylaluminum hydride;
triisobutylaluminum hydride;
triisobutylaluminum; and
diethylaluminum chloride.
Currently, TEA is preferred.
Treated solid oxide compounds are compounds that have had their Lewis acidity increased. The treated solid oxide compound can be produced by a process comprising contacting at least one solid oxide compound with at least one electron-withdrawing anion source to form an anion-containing solid oxide compound. The solid oxide compound is calcined either prior to, during, or after contacting with the electron-withdrawing anion source. Calcining is discussed later in this disclosure.
Generally, the specific surface area of the solid oxide compound after calcining at 500xc2x0 C. is from about 100 to about 1000 m2/g, preferably, from about 200 to about 800 m2/g, and most preferably, from 250 to 600 m2/g.
The specific pore volume of the solid oxide compound is typically greater than about 0.5 cc/g, preferably, greater than about 0.8 cc/g, and most preferably, greater than 1.0 cc/g.
It is preferred when the treated solid oxide compound comprises oxygen and at least one element selected from the group consisting of groups 2-17 of the Periodic Table of Elements, including lanthanides and actinides. However, it is preferred when the element is selected from the group consisting of Al, B, Be, Bi, Cd, Co, Cr, Cu. Fe, Ga, La, Mn, Mo, Ni, Sb, Si, Sn, Sr, Th, Ti, V, W, P, Y, Zn, and Zr. It is important that these treated solid oxide compounds have electron withdrawing ability, while not wanting to be bound by theory, it is believed that a treated solid oxide compound should have a higher Lewis acidity compared to the untreated solid oxide compound. However, it is hard to accurately measure the Lewis acidity of these treated, and untreated solid oxide compounds so various methods have been used. Currently, comparing the activities of treated and untreated solid oxide compounds under acid catalyzed reactions is preferred.
Treated solid oxide compounds can be produced in a variety of ways, such as, for example, by gelling, co-gelling, or impregnation of one compound onto another.
In general, it is preferred to contact at least one solid oxide compound, such as, for example, alumina, zirconia, titania, and mixtures thereof, such as, for example, silica-alumina, with at least one electron-withdrawing anion source compound, to form an anion-containing solid oxide compound, followed by calcining the anion-containing solid oxide compound to form a treated solid oxide compound. In the alternative, a solid oxide compound and an electron-withdrawing anion source compound can be contacted and calcined simultaneously.
The electron-withdrawing anion source compound is any compound that increases the Lewis acidity of the solid oxide under the conditions given herein for producing the treated solid oxide compound. These electron-withdrawing anion source compounds increase the Lewis acidity of the solid oxide compound by contributing to the formation of an electron withdrawing anion, such as, for example, sulfates, halides, and triflates. It should be noted that one or more different electron withdrawing anion source compounds can be used.
The acidity of the solid oxide compound can be further enhanced by using two, or more, electron-withdrawing anion source compounds in two, or more, separate contacting steps. An example of such a process is contacting at least one solid oxide compound with a first electron-withdrawing anion source compound to form a first anion-containing solid oxide compound, followed by calcining the first anion-containing solid oxide compound, followed by contacting with a second electron-withdrawing anion source compound to form a second anion-containing solid oxide compound, followed by calcining the second anion-containing solid oxide compound to form a treated solid oxide compound. It should be noted that the first and second electron-withdrawing anion source compounds can be the same, but are preferably different.
Suitable examples of solid oxide compounds include, but are not limited to, Al2O3, B2O3, BeO, Bi2O3, CdO, Co3O4, Cr2O3, CuO, Fe2O3, Ga2O3, La2O3, Mn2O3, MoO3, NiO, P2O5, Sb2O5, SiO2, SnO2, SrO, ThO2, TiO2, V2O5, WO3, Y2O3, ZnO, ZrO2: and mixtures thereof, such as, for example, silica-alumina and silica-zirconia. It should be noted that solid oxide compounds that comprise Al-O bonds are currently preferred.
Before, during or after calcining, the solid oxide compound can be contacted with an electron-withdrawing anion source compound. The electron-withdrawing anion source compound can be selected from the group consisting of at least one halogen-containing compound, sulfate-containing compound, or triflate-containing compound. The halogen-containing compound is selected from the group consisting of chlorine-containing compounds, bromine-containing compounds, and fluorine-containing compounds. The halogen-containing compound can be in a liquid phase, or preferably, a vapor phase. Optionally, the solid oxide compound can be calcined at 100 to 900xc2x0 C. before being contacted with the halogen-containing compound.
Any method known in the art of contacting the solid oxide compound with the fluorine-containing compound can be used in this invention. A common method is to impregnate the solid oxide compound with an aqueous solution of a fluoride-containing salt before calcining, such as ammonium fluoride [NH4F], ammonium bifluoride [NH4HF2], hydrofluoric acid [HF], ammonium silicofluoride [(NH4)2SiF6], ammonium fluoroborate [NH4BF4], ammonium fluorophosphate [NH4PF6], and mixtures thereof.
In a second method, the fluorine-containing compound can be dissolved into an organic compound, such as an alcohol, and added to the solid oxide compound to minimize shrinkage of pores during drying. Drying can be accomplished by an method known in the art, such as, for example, vacuum drying, spray drying, flashing drying, and the like.
In a third method, the fluorine-containing compound can be added during the calcining step. In this technique, the fluorine-containing compound is vaporized into the gas stream used to fluidize the solid oxide compound so that it is fluorided from the gas phase. In addition to some of the fluorine-containing compounds described previously, volatile organic fluorides can be used at temperatures above their decomposition points, or at temperatures high enough to cause reaction. For example, perfluorohexane, perfluorobenzene, trifluoroacetic acid, trifluoroacetic anhydride, hexafluoroacetylacetonate, and mixtures thereof can be vaporized and contacted with the solid oxide compound at about 300 to about 600xc2x0 C. in air or nitrogen. Inorganic fluorine-containing compounds can also be used, such as hydrogen fluoride or even elemental fluorine.
Generally, the amount of fluorine present is about 2 to about 50 weight percent fluorine based on the weight of the treated solid oxide compound before calcining or the amount added to a precalcined solid oxide compound. Preferably, it is about 3 to about 25 weight percent, and most preferably, it is 4 to 20 weight percent fluorine based on the weight of the treated solid oxide compound before calcining or the amount added to a precalcined solid oxide compound.
Any method known in the art of contacting the solid oxide compound with the chlorine-containing compound or bromine-containing compound can be used in this invention. Generally, the contacting is conducted during or after calcining, preferably during calcining. Any suitable chlorine-containing compound or bromine-containing compound that can deposit chlorine or bromine or both on the solid oxide compound can be used. Suitable chlorine-containing compounds and bromine-containing compound include volatile or liquid organic chloride or bromide compounds and inorganic chloride or bromide compounds. Organic chloride or bromide compounds can be selected from the group consisting of carbon tetrachloride, chloroform, dichloroethane, hexachlorobenzene, trichloroacetic acid, bromoform, dibromomethane, perbromopropane, phosgene, and mixtures thereof Inorganic chloride or bromide compounds can be selected from the group consisting of gaseous hydrogen chloride, silicon tetrachloride, tin tetrachloride, titanium tetrachloride, aluminum trichloride, boron trichloride, thionyl chloride, sulfuryl chloride, hydrogen bromide, boron tribromide, silicon tetrabromide, and mixtures thereof Additionally, chlorine and bromine gas can be used.
If an inorganic chlorine-containing compound or bromine-containing compound is used, such as titanium tetrachloride, aluminum trichloride, or boron trichioride, it also can be possible to contact the chlorine-containing compound or bromine-containing compound with the solid oxide compound after calcining, either by vapor phase deposition or even by using an anhydrous solvent.
Generally, the amount of chlorine or bromine used is from about 0.01 to about 10 times the weight of the treated solid oxide compound before calcining or the amount added to a precalcined solid oxide compound, preferably it is from about 0.05 to about 5 times, most preferably from 0.05 to 1 times the weight of the treated solid oxide compound before calcining or the amount added to a precalcined solid oxide compound.
In another embodiment of this invention, the treated solid oxide compound can be produced by a process comprising contacting at least one solid oxide compound with at least one electron-withdrawing anion source and at least one metal salt compound. In general, it is preferred to contact at least one solid oxide compound, such as, for example, alumina, zirconia, titania, and mixtures thereof, or with mixtures of other solid oxide compounds such as, for example, silica-alumina, with at least one metal salt compound and at least one electron-withdrawing anion source compound, to form an anion- and metal-containing solid oxide compound, followed by calcining the anion- and metal-containing solid oxide compound to form a treated solid oxide compound. In the alternative, a solid oxide compound, a metal salt compound, and an electron-withdrawing anion source compound can be contacted and calcined simultaneously. In another alternative, the metal salt compound and the electron-withdrawing anion source compound can be the same compound.
The metal salt compound is any compound that increases the Lewis acidity of the solid oxide compound under the conditions given herein for producing the treated solid oxide compound. It is preferred when the metal in the metal salt is selected from the group consisting of groups IIA-VIIIA and IB-VIIB of the Periodic Table of Elements, including lanthanides and actinides. However, it is preferred when the element is selected from the group consisting of Al, B, Be, Bi, Cd, Co, Cr, Cu, Fe, Ga, La, Mn, Mo, Ni, Sb, Si, Sn, Sr, Th, Ti, V, W, P, Y, Zn and Zr.
To produce the treated solid oxide compound, at least one metal salt compound can be contacted with the solid oxide compound by any means known in the art to produce a metal-containing solid oxide compound. The metal salt compound can be added to the solid oxide compound before calcining, during calcining, or in a separate step after calcining the solid oxide compound.
Generally, the solid oxide compound is contacted with an aqueous or organic solution of the metal salt compound before calcining. For example, the metal can be added to the solid oxide compound by forming a slurry of the solid oxide compound in a solution of the metal salt compound and a suitable solvent such as alcohol or water. Particularly suitable are one to three carbon atom alcohols because of their volatility and low surface tension. A suitable amount of the solution is utilized to provide the desired concentration of metal after drying. Any water soluble or organic soluble metal salt compound is suitable that can impregnate the solid oxide compound with metal. For example, the drying can be completed by suction filtration followed by evaporation, vacuum drying, spray drying, or flash drying.
If the metal is added to the solid oxide compound after calcination, one preferred method is to impregnate the solid oxide compound with a hydrocarbon solution of the metal salt compound.
Generally, the amount of metal present in the metal-containing solid oxide compound is in a range of about 0.1 to about 30 weight percent metal where the weight percent is based on the weight of the metal-containing solid oxide compound before calcining or the amount added to a precalcined solid oxide compound. Preferably, the amount of metal present in the metal-containing solid oxide compound is in a range of about 0.5 to about 20 weight percent metal based on the weight of the metal-containing solid oxide compound before calcining or the amount added to a precalcined solid oxide compound. Most preferably, the amount of metal present in the metal-containing solid oxide compound is in a range of 1 to 10 weight percent metal based on the weight of the metal-containing solid oxide compound before calcining or the amount added to a precalcined solid oxide compound.
The metal-containing solid oxide compound can then be contacted with at least one electron-withdrawing anion source compounds by the methods discussed previously in this disclosure.
Before, during, or after the solid oxide compound is combined with the metal salt compound or the electron-withdrawing anion source compound to produce the metal-containing solid oxide compound, it is calcined for about 1 minute to about 100 hours, preferably from about 1 hour to about 50 hours, and most preferably, from 3 to 20 hours. Generally, the calcining is conducted at a temperature in a range of about 200xc2x0 C. to about 900xc2x0 C., preferably from about 300xc2x0 C. to about 700xc2x0 C., and most preferably, from 350xc2x0 C. to 600xc2x0 C. The calcining can be conducted in any suitable atmosphere. Generally, the calcining can be completed in an inert atmosphere. Alternatively, the calcining can be completed in an oxidizing atmosphere, such as, oxygen or air, or a reducing atmosphere, such as, hydrogen or carbon monoxide.
In order to obtain high activity from the organometal compounds discussed previously, it is necessary to first contact the organometal compound and the first organoaluminum compound to produce an organometal/organoaluminum mixture. Then, the organometal/organoaluminum mixture is injected into a reactor along with the treated solid oxide compound and optionally, the second organoaluminum compound can be added as a cocatalyst. The concentration of the first organoaluminum compound in the organometal/organoaluminum mixture ranges from about 0.1 to about 10 molar, preferably from about 0.3 to about 5 molar, most preferably from 0.5 to 2.5 molar. The concentration of the organometal compound in the organometal/organoaluminum mixture ranges from about 0.001 and about 1.0 molar, preferably between about 0.005 and about 0.5 molar, most preferably between 0.01 and 0.1 molar.
Another embodiment of this invention is to pretreat the catalyst composition with monomer at low temperature for a short time to obtain a small amount of polymer on the catalyst composition before the main polymerization reaction at higher temperatures. This process is called prepolymerization and can improve activity still further. Preferably, the catalyst composition is pretreated with ethylene at a temperature of less than 40xc2x0 C., most preferably less than 30xc2x0 C. for a period of about 1 to about 120 minutes, preferably from 10 to 70 minutes.
A weight ratio of the second organoaluminum compound to the treated solid oxide compound in the catalyst composition ranges from about 5:1 to about 1:1000, preferably, from about 3:1 to about 1:100, and most preferably, from 1:1 to 1:50.
A weight ratio of the treated solid oxide compound to the organometal compound in the catalyst composition ranges from about 10,000:1 to about 1:1, preferably, from about 1000:1 to about 10:1, and most preferably, from 250:1 to 20:1. These ratios are based on the amount of the components combined to give the catalyst composition.
After contacting, the catalyst composition comprises a post-contacted organometal compound, a post-contacted first organoaluminum compound, a post-contacted treated solid oxide compound, and, optionally, a post-contacted second organoaluminum compound. Preferably, the post-contacted treated solid oxide compound is the majority, by weight, of the catalyst composition. Often times, specific components of a catalyst are not known, therefore, for this invention, the catalyst composition is described as comprising post-contacted compounds.
A weight ratio of the post-contacted second organoaluminum compound to the post-contacted treated solid oxide compound in the catalyst composition ranges from about 5:1 to about 1:1000, preferably, from about 3:1 to about 1:100, and most preferably, from 1:1 to 1:50.
A weight ratio of the post-contacted treated solid oxide compound to the post-contacted organometal compound in the catalyst composition ranges from about 10,000:1 to about 1:1, preferably, from about 1000:1 to about 10:1, and most preferably, from 250:1 to 20:1. These ratios are based on the amount of the components combined to give the catalyst composition.
The catalyst composition of this invention has an activity greater than 100 grams of polymer per gram of treated solid oxide compound per hour, preferably greater than 500, and most preferably greater than about 1,000. This activity is measured under slurry polymerization conditions, using isobutane as the diluent and with a polymerization temperature of 90xc2x0 C., and an ethylene pressure of 550 psig. The reactor should have substantially no indication of any wall scale, coating or other forms of fouling.
One of the important aspects of this invention is that no aluminoxane needs to be used in order to form the catalyst composition. Aluminoxane is an expensive compound that greatly increases polymer production costs. This also means that no water is needed to help form such aluminoxanes. This is beneficial because water can sometimes kill a polymerization process. Additionally, it should be noted that no fluoro-organo borate compounds need to be used in order to form the catalyst composition. It should be noted that organochromium compounds and MgCl2 are not needed in order to form the catalyst composition. Although aluminoxane, fluoro-organo borate compounds, organochromium compounds, and MgCl2 are not needed in the preferred embodiments, these compounds can be used in other embodiments of this invention.
In another embodiment of this invention, a process comprising contacting at least one monomer and the catalyst composition to produce a polymer is provided. The term xe2x80x9cpolymerxe2x80x9d as used in this disclosure includes homopolymers and copolymers. The catalyst composition can be used to polymerize at least one monomer to produce a homopolymer or a copolymer. Usually, homopolymers are comprised of monomer residues, having 2 to about 20 carbon atoms per molecule, preferably 2 to about 10 carbon atoms per molecule. Currently, it is preferred when at least one monomer is selected from the group consisting of ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 3-ethyl-1-hexene, 1 -heptene, 1-octene, 1-nonene, 1-decene, and mixtures thereof.
When a homopolymer is desired, it is most preferred to polymerize ethylene or propylene. When a copolymer is desired, the copolymer comprises monomer residues and one or more comonomer residues, each having from about 2 to about 20 carbon atoms per molecule. Suitable comonomers include, but are not limited to, aliphatic 1-olefins having from 3 to 20 carbon atoms per molecule, such as, for example, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, and other olefins and conjugated or nonconjugated diolefins such as 1,3-butadiene, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, 1,4-pentadiene, 1,7-hexadiene, and other such diolefins and mixtures thereof. When a copolymer is desired, it is preferred to polymerize ethylene and at least one comonomer selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-decene. The amount of comonomer introduced into a reactor zone to produce a copolymer is generally from about 0.01 to about 10 weight percent comonomer based on the total weight of the monomer and comonomer, preferably, about 0.01 to about 5, and most preferably, 0.1 to 4. Alternatively, an amount sufficient to give the above described concentrations, by weight, in the copolymer produced can be used.
Processes that can polymerize at least one monomer to produce a polymer are known in the art, such as, for example, slurry polymerization, gas phase polymerization, and solution polymerization. It is preferred to perform a slurry polymerization in a loop reaction zone. Suitable diluents used in slurry polymerization are well known in the art and include hydrocarbons which are liquid under reaction conditions. The term xe2x80x9cdiluentxe2x80x9d as used in this disclosure does not necessarily mean an inert material; it is possible that a diluent can contribute to polymerization. Suitable hydrocarbons include, but are not limited to, cyclohexane, isobutane, n-butane, propane, n-pentane, isopentane, neopentane, and n-hexane. Furthermore, it is most preferred to use isobutane as the diluent in a slurry polymerization. Examples of such technology can be found in U.S. Pat. Nos. 4,424,341; 4,501,885; 4,613,484; 4,737,280; and 5,597,892; the entire disclosures of which are hereby incorporated by reference.
The catalyst compositions used in this process produce good quality polymer particles without substantially fouling the reactor. When the catalyst composition is to be used in a loop reactor zone under slurry polymerization conditions, it is preferred when the particle size of the solid oxide compound is in the range of about 10 to about 1000 micrometers, preferably about 25 to about 500 micrometers, and most preferably, 50 to 200 micrometers, for best control during polymerization.
In a more specific embodiment of this invention, a process is provided to produce a catalyst composition, the process comprising (optionally, xe2x80x9cconsisting essentially of,xe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d):
(1) contacting [2-(xcex75-cyclopentadienyl)-2-(xcex75-fluoren-9-yl)hex-5-ene]zirconium(IV) dichloride with TEA to produce an organometal/TEA mixture;
wherein the concentration of TEA in the organometal/TEA mixture ranges from 0.5 to 2.5 molar;
wherein the concentration of organometal in the organometal/TEA mixture ranges from 0.01 to 1 molar;
(2) combining a chlorided, zinc-containing alumina and the organometal/TEA mixture to produce the catalyst composition;
wherein the chlorided, zinc-containing alumina is produced by a process comprising contacting alumina with an aqueous solution of zinc chloride to produce a zinc-containing alumina, calcining said zinc-containing alumina at about 600xc2x0 C. for three hours to produce a calcined zinc-containing alumina, and while calcining, contacting the zinc-containing alumina with carbon tetrachloride to produce the chlorided, zinc-containing alumina.
Hydrogen can be used with this invention in a polymerization process to control polymer molecular weight.
After the polymers are produced, they can be formed into various articles, such as, for example, household containers and utensils, film products, drums, fuel tanks, pipes, geomembranes, and liners. Various processes can form these articles. Usually, additives and modifiers are added to the polymer in order to provide desired effects. It is believed that by using the invention described herein, articles can be produced at a lower cost, while maintaining most, if not all, of the unique properties of polymers produced with metallocene catalysts.